Photogravure-printing machine



Jan. 21, 1930. w. GREAVES 1,744,456

' ,PHOTOGRAVURE PRFINTING MACHINE Filed Oct. 27. 1928 Patented Jan. 21, 1930 WATENT GFFIQE WILFRED GREAVES, OF SHADWELL, NEAR LEEJDE, ENGLAND, ASSIGNOR TO LINOTYPE AND lvIAGI-IINERY LIMITED, OF LONDON, ENGLAND PHOTOGRAV'UREJPRINTING MACHINE Application filed October 27, 1928, Serial No. 315,367, and in Great Britain October 29, 1927.

This invention relates to rotary photogravure printing machines, and has for its object to provide new or improved means for flooding the curvilinear plate or printing surfaces with ink by spraying.

A principal feature of the invention consists in the provision of means in the ink supply system whereby the spray may be cut off at some part of the revolution of the plate or printing cylinder.

These printing surfaces are sometimes the surfaces of complete cylinders and sometimes the surfaces of plates stretched partly or al most completely around the printing cylinders, with a gap of greater or smaller widthbetween the proximate ends of the actual print ing area. To avoid undesirable reiteration, the term cylindrical is hereinafter used to designate all the aforesaid curvilinear printing surfaces and at the same time to distmguish the invention from hitherto proposed arrangements employing flat printing surfaces, and wherein it was suggested to rotate these surfaces always in a given horizontal plane and to emit ink from spraying ets only at the periods at which these surfaces were passing over the said jets.

As the invention is particularly advantageous in its application to rotary photogra vure printing machines employing printing cylinder whose printing surface is constltuted by a photogravure plate having its ends secured within a groove or gap in the cylmder, said invention is hereinafter described with reference to a constructional form applied to a machine of that character.

In the accompanying drawings:

Figure 1 is a side elevation of said constructional form of the invention, the pertinent parts of the machine to which it is applied being indicated diagrammatically.

Figure 2 is an elevation, partly broken away, as viewed. in the direction indicated by the arrow in Figure 1, and

Figure 3 is an enlarged detail view of a part of Figure 1.

1 represents the machine frame, 2 the plate cylinder and 3 the impression cylinder of a rotary photogravure printing machine, of which the plate cylinder 2 is adapted to support a printing plate having its ends secured thereto within the gap 4 by any suitable means.

The ink supply system comprises an ink 'w 1 a I" 311111 glen o, it pump G supplyrng ink c plessure, through plpes 7, S, to a spray pipe 9 extending longitudinally of the plate cylinder 2.

According to the constructional form of the invention now being dealt with, the pipe 9 is provided with a longitudinal slot 10 of a length equal to the full width of the printing cylinder face, through which ink is s arayed onto the printing plate.

To provide for the cutting 0d of the spray during a certain period of the revolution of the cylinder 2, a wedge-shaped bar 11 is fitted within the pipe slot 10 with a capacity for radial movement to open and close the slot. At each end of the bar 11 a rod 11 fast to the bar, is slidably supported in a guide 12, and the spraying slot 10 is normally kept open by a spring 13 acting on the rod 11 to re tain it in the position in which it is shown in the drawings. Co-operating with each of the rods 11, there is provided a push-rod 14:, slidably mounted in a guide 15, and carrying at its outer end, a roller 16 retained in contact with a cam 17 by a spring 18. The cams 17 rotate with the cylinder 2, and are arranged to hold the rods 14 depressed, and hence, through the rods 11 and wedge bar 11, to close the slot 10, during the passage of the cylinder gap l. past the said slot.

The pump'ti operates continuously, and the amount of ink being passed to the printing surface may be regulated by a valve 19 in the delivery pipe 7, which also allows the surplus ink to return to the trough 5 or the whole of it when the slot 10 is closed.

It will be understood that, as ordinarily, means will be provided for removing surplus ink from the printing plate on cylinder 2, and returning said surplus ink to the trough 5, but as these means form no part of the present invention, it is not deemed necessary to describe same herein or to illustrate them in the drawing.

Having described my invention, I declare that what I claim and desire to secure by Let ters Patent is 1. In a rotary photogravure printing machine, the combination with the cylindrical rotating printing surface, of a slotted pipe relatively to which the said surface rotates in close adjacency, a bar movable to open and close the slot in the pipe and means controlled by the rotation of the printing cylinder adapted to move the said bar.

2. In a rotary photogravure printing machine, the combination with the cylindrical rotating printing surface, of a slotted pipe relatively to which the said surface rotates in close adjacency, a bar movable to open and close the slot in the pipe, means controlled by the rotation of the printing cylinder adapted to move the said bar, an ink-contain ing trough, a continuously operating pump delivering ink from the trough to the slotted pipe, a pipe operatively connecting the pump and slotted pipe and a relief valve in said conneeting pipe adapted to regulate the ink supply when the spray-pipe is delivering ink to the printing surface and permit return of the surplus ink to the trough or the whole of it to said trough when the spray is cut otl.

3. In a rotary photogravure printing machine, the COll'llJlIltltlOl'l with the cylindrical rotating printing surface, of a slotted pipe relatively to which the said surface rotates in close adjacency, a bar movable to open and close the slot in the pipe, means controlled by the rotation of the printing cylinder adapted to move the said bar, springs adapted to maintain the bar in slot-opening position, and a rotating cam adapted to move the bar into the slot-closing position.

4. In a rotary photogravure printing machine, the combination with. the cylindrical rotating printing surface, of a slotted pipe relatively to which the said surface rotates in close adjacency, a bar movable to open and close the slot in the pipe, means controlled by the rotation of the printing cylinder adapted to move the said bar, rods fast to the ends of the bar, springs encircling the rods adapted to maintain the bar in slot-opening position, push-rods adapted to operatively engage the said rods, guides encircling these push-rods, rollers pivoted in the push-rods, rotating cams engaging the rollers and springs bearing on the guides and holding the rollers constantly in contact with the cams.

5. In a rotary photogravure printing machine, the combination with the cylindrical rotating printing surface, of a slotted pipe relatively to which the said surface rotates in close adjacency, abar movable to open and close the slot in the pipe, means controlled by the rotation of the printing cylinder adapted to move the said bar, rods fast to the ends of the bar, springs encircling the rods adapted to maintain the bar in slotopening position, push-rods adapted to operatively engage the said rods, guides encircling these push-rods, rollers pivoted in the push-rods, rotating cams engaging the rollers, springs bearing 011 the guides and holding the rollers constantly in contact with the cams, an ink-containing trough, a continuously operating pump dclivcring'ink from the trough to the slotted pipe, a pipe operatively connecting the pump and slotted pipe and relief alve in said connecting pipe adapted to regulate the ink supply when the spray-pipe is delivering ink to the printing surface and permit return of the surplus ink to the trough or the whole of it to said trough when the spray is cut off.

In witness whereof I have aflixed my signature hereto.

IVILFRED GR EAVES. 

